Absorbent articles such as paper diapers (for infants and adults), sanitary napkins, incontinence articles, training pants or the like are articles that absorb bodily fluids, such as urine excreted from a wearer, by means of an absorber that makes use of a super absorbent polymer (hereinafter referred to as an “SAP”), fluffy pulp or the like.
Conventional absorbent articles prevent leakage by closely attaching an absorber to the surface of the body of a wearer without any gap and by transferring the excreted bodily fluids from the surface of the absorber to the inside thereof to be absorbed therein.
Such closely-attached state of the absorber to the body of the wearer is achieved by applying a “pressing force from the exterior” to the absorber. This will be described in more detail by taking an infant's diaper as an example.
In infant's diapers, as a means for generating a “pressing force from the exterior,” various stretchable materials (similar to those used in pantyhose, supporters, competition swimsuits and the like) are arranged at various parts. Especially in recent years, for tapeless underpants-type diapers which have become a main trend for infant' diapers, since they are mainly intended for infants when their body movement becomes active (approximately 6 kg or more in body weight), it is necessary to make use of a stretchable material.
In general, the following stretchable materials are used for underpants-type diapers:
(1) A waist gather band (waist part stretchable body): the waist gather band serves as a fixing band that connects a front end part and a rear end part of a diaper body to each other, attaches the diaper closely around the waist and prevents the diaper from sliding down;(2) Shirring gathers or trunk gathers (trunk part maintaining stretchable body): the shirring or trunk gathers are present so as to cover each of a back surface and a ventral surface of the diaper and exhibit functions of pressing the absorber in the vicinities of the back surface and the ventral surface against the surface of the wearer's body; and(3) Leg gathers (leg part stretchable body): the leg gathers provide sealing, in the vicinity of the crotch part, so that no gap is formed between the diaper body and the wearer's body and play a role of a dam (bank) that prevents leakage from the side surfaces of the absorber. The leg gathers are classified into the following three types depending on their roles, and each type may be used alone or two or more types may be used in combination.(3a) First inner leg gather (ILG): the first ILG is provided above the absorber or on a side edge of the absorber, includes a stretchable head part and a leg part made of a non-woven fabric, and usually has a standing geometry.(3b) Second inner leg gather (ILG): the second ILG is provided on the side edge of the absorber or on the exterior thereof, includes a stretchable head part and a leg part made of a non-woven fabric, and usually has a standing geometry.(3c) Outer leg gather (OLG) or gusset gather: the OLG or gusset gather is provided by sandwiching a stretchable material by a top sheet and a leak preventer from both side surfaces at the side edge of the diaper body, and it is usually flat; however, it is, in some cases, folded on the inward side and is used in a standing geometry.